Liquids can be filled and packaged in a variety of different containers, including ampoules made from glass or plastic.
Traditionally, glass has been the predominant packaging material for sterile pharmaceutical liquids; however, aseptic processing, involving filling open glass bottles or phials, sets high demands on the manufacturer to obtain aseptic conditions at all times, especially for large-volume containers.
Handling of glass containers always involves a certain risk for lacerations and glass splinters. It has also been shown that glass ampoules generate a fine array of small glass particles during opening. The sub-atmospheric pressure inside the ampoule tends to draw such particles inside the ampoule on opening. US 2006/0163109 describes an ampoule with an air entry port in the neck intended to assist with the reliable filling of a syringe or needle base.
Single doses of liquid products such as pharmaceuticals are now frequently packaged in plastic ampoules. The user is required to open one end of the ampoule in order to access the product. To facilitate this, the body of an ampoule, which forms the reservoir for the contents, typically narrows towards the top to form a neck which then widens once more to form a cul-de-sac or bulb in the head. The neck and head are designed to allow the head to be easily detached by breaking or tearing of the neck along a tear line, providing an opening for the flow of product from the body of the ampoule via a channel in the neck. The present invention relates especially to such ampoules.
Pharmaceutical suspensions contain ingredients which are undissolved within a carrier liquid and thus prone to settling on the bottom or sides of the ampoule during storage. If the ampoules are inverted or stored upside-down settled suspension may pass down the neck into the head of the ampoule. In certain ampoules the narrowing of the flow path between the head and the neck is such that even once the ampoule is upright the surface tension of the liquid is sufficient to hold the suspension within the head. Thus, when the user detaches the head of the ampoule, an amount of product, whether liquid containing suspension or settled suspension, is retained within the head and thus a portion of the suspension is lost and not delivered to the patient.
The amount of suspension, i.e. active ingredient, in such pharmaceutical compositions may be very low with respect to the volume of liquid. Thus the proportion of the suspension that can settle in or around the head may be high, so loss of suspension in this way can be highly significant, resulting in significant reduced effectiveness of the medication.
A related problem is that ampoule contents retained within the head may on opening be transferred to the fingers of the patient and may lead to further transfer for example onto the eyes or the face of the patient if the pharmaceutical is not washed off the fingers immediately. This problem applies to both solution and suspension pharmaceuticals in plastic ampoules.
An option is to enlarge the diameter of the flow path between the neck and the head so that liquid is not retained in the head and so that once the ampoule is correctly orientated the liquid returns to the reservoir. However, while the ampoule was upside-down the active ingredient of the suspension may have settled in the head and may remain there. Thus, when the user dispenses the medication the volume may appear to be correct and it would not be apparent that a portion of the active ingredient would be lost when the head is detached.
US 2004/0182883 describes a hermetically sealed container with a constriction in the neck intended to eliminate any dripping or splashing when the cap is removed along a tear line. A problem, however, with this container is that the constriction may not prevent settled suspension passing into the head. A further problem is that dispensing of the container contents is made difficult by the narrowness of the constriction. In addition, formation of such narrow constrictions is not easily and reliably achievable, and hence this type of container is not practical to make on a large scale for pharmaceutical uses or may require expensive modification of existing machinery.
An object of the present invention is to solve or at least ameliorate the above-identified issues. An object of preferred embodiments of the invention is to provide plastics ampoules which retain less suspension in their head portions after inversion during storage.